Php Server Variables

Php Server Variables Not Working
Php Server Path
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Php Server Url

PHP - $SERVER Variable By: Mr. Malhar Lathkar, Tutorials Point India Private Limited.
PHP - Global Variables - Scope can be defined as the range of availability a variable has to the program in which it is declared. PHP variables can be one of four scope types −.

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PHP Server Variables. PHP stores a list of information about the server. Fashion canvas wall art. This will include things like, the browser the visitor is using, the IP address, and which web page the visitor came from. Here's a script to try with those three Server Variables. In many applications we need to pass variables through query string. For example we want to display the product details where product ID is to be passed in query string through a variable. The product ID can be collected from a table so we don't know what is the value but we can use the variable which stores the product ID.

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Scope can be defined as the range of availability a variable has to the program in which it is declared. Codelobster ide. PHP variables can be one of four scope types −

Local variables
Function parameters
Global variables
Static variables.

Global Variables

In contrast to local variables, a global variable can be accessed in any part of the program. However, in order to be modified, a global variable must be explicitly declared to be global in the function in which it is to be modified. This is accomplished, conveniently enough, by placing the keyword GLOBAL in front of the variable that should be recognized as global. Placing this keyword in front of an already existing variable tells PHP to use the variable having that name. Consider an example −

This will produce the following result −

php_variable_types.htm

There are different ways by which values of variables can be passed between pages. One of the ways is to use the URL to pass the values or data. Here the biggest advantage is we can pass data to a different site even running at different servers. Any scripting language like ASP, JSP, PHP or Perl running at receiving end can process and collect the value from the query string or from the URL.

Php Server Variables Not Working

Easy to save the URL or bookmark it for frequent use.
Copy the URL and send it to a friend to refer.

Here one main concern is the data gets exposed in address bar of the browser and can be easily accessible by using browser history. So it is not a good idea to pass sensitive data like password through the URL to different pages or different sites.

Video Tutorial on passing data between pages

Here is an example of passing data through URL within a site.

When the above link is clicked, page2.php gets the variables id and user with data 2489 and tom respectively. Here is the code to collect data in PHP.
The address of page2.php can be replaced with any site name and the same data can be passed to another site running in any server. Like this Php Server Variables

Passing data outside

Demo of passing data through a form
You can see in the above case the values can be posted to another site. Note that after the page name we are using question mark ( ? ) to start the variable data pair and we are separating each variable data pair with one ampersand ( & ) mark.

Submitting form values through GET method

Php Server Path

A web form when the method is set to GET method, it submits the values through URL. So we can use one form to generate an URL with variables and data by taking inputs from the users. The form will send the data to a page within the site or outside the site by formatting a query string.

Submitting a form through POST method

By post method of form submission we can send more number or length of data. Sensitive information like password does not get exposed in URL by POST method, so our login forms we should use POST method to submit data. This is how we collect data submitted by POST method in PHP
Difference between GET and POST

issues	GET	POST
Browser History	Data remain in Browser History	Data Not available in Browser History
Bookmark	URL with Data can be bookmarked	No data is available in URL to bookmark the page
Data Length Restiction	The restriction (of URL ) is applicable	No Restriction
cached	Can be cached	No meaningful caching
Sensitive Data	Data like password , pin etc are exposed through URL so they should not be passed using GET method	Better than GET method as data is not exposed through URL

Collecting data submitted by either GET or POST method

If a page is receiving a data which can come in any one of the method GET or POST then how to collect it ? Here we are not sure how to collect the data. So we will use like this.

Php Server Variables W3schools

Every scripting language pages has its own way of receiving the data from the URL

While receiving the data based on the server settings the values will be available to the pages. Here in a server running PHP will have to see the global settings of the server on how to collect the data. Same way in ASP environment running VB script the data can be collected and assigned like this

Passing data within the site using URL

The same principle is used like above to send the data within the site using URL. A query sting can be formatted with a link or a form can be used with get method to pass variables between pages.

Passing the data between the site through URL

Like above data can be passed to different pages of sites using URL . The best use is directly linking to a page dip inside another site by formatting a query sting. Like this

Passing variables through query string

In many applications we need to pass variables through query string. For example we want to display the product details where product ID is to be passed in query string through a variable. The product ID can be collected from a table so we don't know what is the value but we can use the variable which stores the product ID.
For example let us say we have collected product id from the product table. Read the tutorial on how to collect data from table. Our link with query string will have something like this. You can directly display like this also.

Chang of data while passing through URL

There is a problem in sending data other than plain text through browser. Empty space and some characters like & if present in the data , will create problem. To maintain the data integrity we have to encode the data before sending them though URL and then decode them again to get back the original data. In PHP encode command is used and in ASP VBScript the command is Server.URLEncode(string)

Security issues while posting data through URL

The most common type of security problem in using data from URL is injection attack. We must sanitize the date before using inside our script or generating any query to manage database.
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